Sigma/pi versus pi/pi conjugation: DFT studies on oligocyclopropenones and related systems.
DFT studies on oligocyclopropenones and related systems 5(n)-9(n) are reported. A strong sigma/pi interaction between the pi system and the sigma framework of the three-membered rings is observed in almost all cases, leading to a perpendicular arrangement of the pi systems in the most favored conformation. Also the shape of cyclic congeners is strongly influenced by sigma/pi interactions.
Werz
Daniel B
DB
Institut für Organische und Biomolekulare Chemie der Georg-August-Universität Göttingen, Göttingen, Germany. dwerz@gwdg.de
Düfert
Alexander
A